title: Active-site inhibitors modulate the dynamic properties of human monoacylglycerol lipase: a hydrogen exchange mass spectrometry study.
abstract: Human monoacylglycerol lipase (hMGL) regulates endocannabinoid signaling primarily by deactivating the lipid messenger 2-arachidonoylglycerol. Agents that carbamylate hMGLs catalytic Ser(122) constitute a leading class of therapeutically promising hMGL inhibitors. We have applied peptide-level hydrogen/deuterium exchange mass spectrometry to characterize hMGL's conformational responses to two potent carbamylating inhibitors, AM6580 (irreversible) and AM6701 (slowly reversible). A dynamic, solvent-exposed lid domain is characteristic of hMGL's solution conformation. Both hMGL inhibitors restricted backbone enzyme motility in the active-site region and increased substrate binding-pocket solvent exposure. Covalent reaction of AM6580 with hMGL generates a bulkier carbamylated Ser(122) residue as compared to the more discrete Ser(122) modification by AM6701, a difference reflected in AM6580's more pronounced effect upon hMGL conformation. We demonstrate that structurally distinct carbamylating hMGL inhibitors generate particular conformational ensembles characterized by region-specific hMGL dynamics. By demonstrating the distinctive influences of two hMGL inhibitors on enzyme conformation, this study furthers our understanding at the molecular level of the dynamic features of hMGL interaction with small-molecule ligands.
authors.affiliation: Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University , Boston, Massachusetts 02115-5000, United States.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Karageorgos
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wales
authors.forename: David R
authors.initials: DR
authors.lastname: Janero
authors.forename: Nikolai
authors.initials: N
authors.lastname: Zvonok
authors.forename: V Kiran
authors.initials: VK
authors.lastname: Vemuri
authors.forename: John R
authors.initials: JR
authors.lastname: Engen
authors.forename: Alexandros
authors.initials: A
authors.lastname: Makriyannis
mesh_terms: D020134:Catalytic Domain; D004791:Enzyme Inhibitors / Q000737:chemistry*; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008958:Models, Molecular; D008994:Monoacylglycerol Lipases / Q000037:antagonists & inhibitors*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D006859:Hydrogen; D008994:Monoacylglycerol Lipases